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Frequently in the news there is discussion regarding the use of GMO's in
crops and foods. The term "genetically modified organism" (GMO) was
originally used by the molecular biology scientific community to denote a
living organism that had been genetically modified by inserting a gene
from an unrelated species. Incorporation of genes from an unrelated
species does not occur in nature through sexual reproduction and thus,
various types of sophisticated technologies are used to accomplish this.
These types of plants are generally called "transgenics". Transgenic
technology has been used in over 40 species of plants including corn,
cotton, tomatoes, potatoes, soybeans, tobacco, rice, cranberries, papayas,
raspberries, chrysanthemums, gladioli, petunias, poplars, spruce, and
walnuts. In crop plants, the technology has generally been used to
incorporate insect resistance or herbicide tolerance. More recently,
transgenic rice strains having high vitamin A or high iron content have
been developed. In the future, transgenic plants may be used as
"bioreactors" to produce large quantities of inexpensive pharmaceuticals,
polymers, industrial enzymes, as well as modified oils, starches, and
proteins.
How Are Genetically Modified Organisms Different
From
The End-Products of Conventional Breeding?
Organisms that are highly related can usually intermate through
sexual reproduction. Most conventional breeding efforts are focused on
making crosses amongst highly related strains of a species and then
selecting among the offspring. This same sort of crossing takes place in
nature. The difference between what occurs in nature and in a breeding
program, is that the breeder selects which two strains to intermate
through crossing. Such conventional breeding methods have been used as
long man has tried to domesticate plants and animals.
The more unrelated two organisms are, the less likely that sexual
reproduction would successfully result in viable offspring. Several
decades ago breeding methods were developed that allow for closely
related species or even somewhat distantly related species to be
successfully mated. This allowed for the transfer of useful genes from
related species into crop plants that may not have normally survived in
nature because it would be such an extremely rare event. With these
methods, breeders had access to a wider range of genes that occurred in
nature to improve crop plants. Tremendous success has been demonstrated
in crops by using these genes for building resistance to insects and
diseases and for tolerance to abiotic stresses.
Biotechnology methods have now been developed that allow researchers
to completely by-pass sexual reproduction and directly insert a gene
into a cell that will be the basis of a new plant. Thus, new
combinations of genes can be created in a genetically modified organism
that would never be found in nature. The recently developed "Golden
Rice" is an example of a GMO that has enhanced Vitamin A content due to
the incorporation of genes from a microbe and from daffodils into rice.
Regular white milled rice has insignificant levels of Vitamin A. Thus,
Vitamin A enhanced rice may improve the diet of people in third world
countries that rely upon rice as their main food source.
Source:
http://www.ars.usda.gov/Research/docs.htm?docid=7205
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